The present invention relates to packet communications apparatus and a network system, and more particularly, to packet communications apparatus and a network system arranged for preventing the unfair use of networking service, wherein a LAN switch, router, etc is used as that apparatus.
Recently, it has been appreciated that information security techniques for restricting network use are required in order to ensure the confidentiality of information transferred over networks. On the other hand, with convenient use of networks taken into consideration, networking is implemented such that, only by connecting a terminal to a network, the terminal user can use networking service in some Local Area Networks (LANs), typically, for example, a 802.3 network of Carrier Sense Multiple Access with Collision Detection (CSMA/CD) type, the specifications thereof being prescribed by the Institute of Electrical and Electronics Engineers, Inc. (IEEE).
For a network using a Dynamic Host Configuration Protocol (DHCP) standardized by the Internet Engineering Task Force (IETF), when a terminal is newly connected to the network, its address is automatically assigned to it. By combining these networks or LANs with mobile terminals such as notebook-size personal computers, a (public) network parts system has appeared, allowing a terminal user to use networking service from anywhere, whenever necessary. Technique regarding the network ports system has been disclosed in, for example, JP-A-68765/1999.